> ## Documentation Index > Fetch the complete documentation index at: https://docs.z.ai/llms.txt > Use this file to discover all available pages before exploring further. # Tokenizer > `Tokenizer` is used to split text into `tokens` recognizable by the model and calculate the count. It receives user input text, processes it through the model for tokenization, and finally returns the corresponding `token` count. It is suitable for text length evaluation, model input estimation, dialogue context truncation, cost calculation, etc. ## OpenAPI ````yaml POST /paas/v4/tokenizer openapi: 3.0.1 info: title: Z.AI API description: Z.AI API available endpoints license: name: Z.AI Developer Agreement and Policy url: https://chat.z.ai/legal-agreement/terms-of-service version: 1.0.0 contact: name: Z.AI Developers url: https://chat.z.ai/legal-agreement/privacy-policy email: user_feedback@z.ai servers: - url: https://api.z.ai/api description: Production server security: - bearerAuth: [] paths: /paas/v4/tokenizer: post: summary: Text Tokenizer description: >- `Tokenizer` is used to split text into `tokens` recognizable by the model and calculate the count. It receives user input text, processes it through the model for tokenization, and finally returns the corresponding `token` count. It is suitable for text length evaluation, model input estimation, dialogue context truncation, cost calculation, etc. requestBody: content: application/json: schema: $ref: '#/components/schemas/TokenizerRequest' examples: Text Tokenization Example: value: model: glm-4.6 messages: - role: user content: >- What opportunities and challenges will the Chinese large model industry face in 2025? required: true responses: '200': description: Business processing successful content: application/json: schema: $ref: '#/components/schemas/TokenizerResponse' default: description: The request has failed. content: application/json: schema: $ref: '#/components/schemas/Error' components: schemas: TokenizerRequest: type: object required: - model - messages properties: model: type: string description: The model code to be called. example: glm-4.6 default: glm-4.6 enum: - glm-4.6 - glm-4.6v - glm-4.5 messages: type: array description: >- The current conversation message list as the model’s prompt input, provided in JSON array format, e.g.,`{“role”: “user”, “content”: “Hello”}`. Possible message types include system messages, user messages. Note: The input must not consist of system or assistant messages only. items: oneOf: - title: User Message type: object properties: role: type: string enum: - user description: Role of the message author default: user content: oneOf: - type: array description: >- Multimodal message content, supports text, images, video, file items: $ref: '#/components/schemas/VisionMultimodalContentItem' - type: string description: >- Text message content (can switch to multimodal message above) example: >- What opportunities and challenges will the Chinese large model industry face in 2025? required: - role - content - title: System Message type: object properties: role: type: string enum: - system description: Role of the message author default: system content: oneOf: - type: string description: Message text content example: You are a helpful assistant. required: - role - content - title: Assistant Message type: object description: Can include tool calls properties: role: type: string enum: - assistant description: Role of the message author default: assistant content: oneOf: - type: string description: Text message content example: I'll help you with that analysis. required: - role minItems: 1 tools: type: array description: List of tools the model can call. Supports up to `128` functions. anyOf: - items: $ref: '#/components/schemas/FunctionToolSchema' request_id: type: string description: >- Passed by the user side, needs to be unique; used to distinguish each request, 6–64 characters. If not provided by the user side, the platform will generate one by default. minLength: 6 maxLength: 64 user_id: type: string description: >- Unique ID for the end user, 6–128 characters. Avoid using sensitive information. minLength: 6 maxLength: 128 TokenizerResponse: type: object properties: created: type: integer format: int64 example: 1727156815 id: type: string example: 20241120141244890ab4ee4af84acf description: >- The task sequence number generated by the Zhipu AI Open Platform. Please use this number when calling the request result interface. request_id: type: string example: '1' description: >- The task number submitted by the client or generated by the platform when the request was initiated. usage: type: object properties: prompt_tokens: type: number description: Prompt tokens in this input image_tokens: type: number description: Image tokens in this input video_tokens: type: number description: Video tokens in this input total_tokens: type: number description: Total tokens in this input required: - id - usage Error: required: - code - message type: object description: The request has failed. properties: code: type: integer format: int32 description: Error code. message: type: string description: Error message. VisionMultimodalContentItem: oneOf: - title: Text type: object properties: type: type: string enum: - text description: Content type is text default: text text: type: string description: Text content required: - type - text additionalProperties: false - title: Image type: object properties: type: type: string enum: - image_url description: Content type is image URL default: image_url image_url: type: object description: Image information properties: url: type: string description: >- Image URL or Base64 encoding. Image size limit is under 5M per image, with pixels not exceeding 6000*6000. GLM-5V GLM4.6V series are limited to 150 sheets, GLM4.5V limit 50 sheets. Supports jpg, png, jpeg formats. required: - url additionalProperties: false required: - type - image_url additionalProperties: false - title: Video type: object properties: type: type: string enum: - video_url description: Content type is video URL default: video_url video_url: type: object description: Video information. properties: url: type: string description: >- Video URL address.The video size is limited to within 200 MB, GLM-5V GLM4.6V series are limited to 2 videos, GLM4.5V limit 1 video, and the format supports `mp4`，`mkv`，`mov`. required: - url additionalProperties: false required: - type - video_url additionalProperties: false - title: File type: object properties: type: type: string enum: - file_url description: >- Content type is file URL, not support passing both the `file_url` and `image_url` or `video_url` parameters at the same time. default: file_url file_url: type: object description: File information. properties: url: type: string description: >- File URL address. Only GLM-5V-Turbo, GLM-4.6V, GLM-4.5V supported. Supports formats such as pdf、txt、word、jsonl、xlsx、pptx, with a maximum of 50. required: - url additionalProperties: false required: - type - file_url additionalProperties: false FunctionToolSchema: type: object title: Function Call properties: type: type: string default: function enum: - function function: $ref: '#/components/schemas/FunctionObject' required: - type - function additionalProperties: false FunctionObject: type: object properties: name: type: string description: >- The name of the function to be called. Must be a-z, A-Z, 0-9, or contain underscores and dashes, with a maximum length of 64. minLength: 1 maxLength: 64 pattern: ^[a-zA-Z0-9_-]+$ description: type: string description: >- A description of what the function does, used by the model to choose when and how to call the function. parameters: $ref: '#/components/schemas/FunctionParameters' required: - name - description - parameters FunctionParameters: type: object description: >- Parameters defined using JSON Schema. Must pass a JSON Schema object to accurately define accepted parameters. Omit if no parameters are needed when calling the function. additionalProperties: true securitySchemes: bearerAuth: type: http scheme: bearer description: >- Use the following format for authentication: Bearer [](https://z.ai/manage-apikey/apikey-list) ````